1. Field of Invention
The invention relates to a rotary combustion engine comprising a non-rotary outer casing, a non-rotary inner casing, a power shaft arranged inside the inner casing and provided with an eccentric element, a first eccentric ring between the non-rotary outer casing and the non-rotary inner casing, a second eccentric ring mounted in bearings around the eccentric element of the power shaft and arranged to operate coaxially with the first eccentric ring, a combustion chamber arrangement for burning a mixture of fuel and air supplied into the engine.
2. Description of Related Art
A similar engine is known for example from U.S. Pat. No. 4,033,299, where a driving eccentric ring is fixed off the centre to a power shaft, so that they rotate together at the same speed of rotation. Mobile closing means are arranged to pass through the eccentric ring so as to rotate with the ring and they are sealed from their ends to the inner surface of an outer casing and to the outer surface of an inner casing. A combustion chamber is situation between the outer casing and the eccentric ring. A mixture of fuel and air is supplied laterally from the middle of the engine first into a chamber formed by the inner casing, from which it is sucked into the space between the inner casing and the eccentric ring and further to the combustion chamber between the eccentric ring and the outer casing. In the combustion chamber, the fuel mixture is compressed, ignited and finally removed. All the working phases of the engine take place during one cycle, and there is one explosion of the fuel mixture per one cycle. Suction and exhaust phases occur at different times. The operation corresponds substantially to a two-stroke engine.
A problem with the aforementioned rotary engine as well as all the other prior art rotary engines is the rotation of the driving elements (in this case for example the eccentric ring). These elements have naturally high peripheral speeds and there have been insurmountable problems with the friction and wearing of rotary and non-rotary components, preventing manufacture of a structure that would be able to compete with conventional engines. Another problem is the small combustion chamber, which causes high point temperatures. Also, the explosion is rather ineffective, since the thrust walls have been insufficient with respect to the engine size.